What does Hafnia mean in Latin?

Hafnia, a proper noun, means “Copenhagen”.

What is the genitive of Hafnia?

The genitive singular is Hafniae. Hafnia is feminine, first declension.

In classical Latin, [ˈhaf.ni.a]; in ecclesiastical (church) Latin, [ˈaf.ni.a].

proper noun · femininefirst declension

Hafnia f sg (genitive Hafniae)

Classical[ˈhaf.ni.a]Ecclesiastical[ˈaf.ni.a]

From Late Old Norse hǫfn (“harbour, port”) or Old Danish hafn (“harbour, port”); from Kaupmannahǫfn.